Expandable, blowing agent-containing pellets based on high temperature thermoplastics having a glass transition temperature according to ISO 11357-2-1999 of at least 180° C., wherein the expandable, blowing agent-containing pellets comprise at least one nucleating agent and have a poured density according to DIN ISO 697:1982 in the range from 400 to 900 kg/m3 and a mass in the range from 1 to 5 mg/pellet, processes for production thereof and foam particles obtainable therefrom having a glass transition temperature according to ISO 11357-2-1999 of at least 180° C., wherein the expanded foam particles comprise at least one nucleating agent and have a poured density according to DIN ISO 697:1982 in the range from 10 to 200 kg/m3, and particle foams obtainable therefrom and the use thereof for producing components for aviation.